police surrounded a house in suburban watertown, where dzhokhar tsarnaev was hiding in a boat. a resident tipped them off after .potting blood on the boat an infrared camera helps to track him down. 9000 police officers had been searching all day. >> we are so grateful to be here right now. we're so so grateful to bring justice and a closure to this case, to those families that lost loved ones or suffered injuries. >> locals were overjoyed by the news, cheering police and celebrating in the streets. >> very happy about it, relieved. i live not too far down the street. i had to get out and check it out for myself. >> the suspects are ethnic chechens. the older brother, tamerlan tsarnaev, was killed in a shootout with police. their mother insisted they are innocent, saying they were interested in islam but never talked about jihad. she says she believes to have been framed by police. the two brothers were caught on camera at the boston marathon carrying backpacks. police say they have images of one of the brothers setting his backpack down at the site of the explosion. the search